The present invention relates to an apparatus and method for processing worms for providing the processed worm bodies as an end product or for enabling recovery of valuable by-products from the worm bodies.
Valuable by-products can be simple and as xe2x80x98obviousxe2x80x99 as using the worms as a source of protein e.g. to provide a food supplement for feeding to, inter alia, fish in intensive fish farming operations or as a source of omega oils which may be found in economically viable quantities in the bodies of earthworms. For example, the omega-3 fatty acids DHA (docosahexaenoic acid), EPA (eicosopentaenoic acid), and DPA can be found in earthworm bodies and the market price of such fatty acids compounds at 99% purity is over US$50, 000 per kilogram. The term xe2x80x98wormxe2x80x99 when used in this specification includes an earthworm or marine worm (Chaetipoda), flat-worm (Platyhelminthes), a round-worm (Nematoda), and other suitable invertebrates.
Before the bodies of worms could be used as a protein source, it would be desirable to cleanse the worm bodies of ingested matter and/or remove the digestive tract and/or remove blood from the worm bodies. Also cleansing the digestive tract would be desirable if the worm bodies are to be processed for recovery of substances therefrom e.g. essential oils, acids, etc. Emptying the digestive tract has been proposed in the past by xe2x80x98starvingxe2x80x99 the earthworms e.g. for 24-48 hours by keeping them in moist paper so that they naturally pass ingested matter through their digestive tracts. However, this does not remove the digestive tract or blood from the worm bodies.
It has further been proposed to cut worms longitudinally to expose the insides of the digestive tracts and then washing the split worm bodies. This process and concept has been clearly described in the PCT Patent specification PCT/AU96/00324 (Publication No. W097/19600) by the present applicant.
In PCT/UA96/000324, the method of processing worms for providing or recovering valuable products from the worm bodies has been claimed and such method includes the steps of exposing the insides of the digestive tracts of the worms along substantially the entire lengths thereof and cleansing the worm bodies to remove ingested matter and/or the exposed digestive tracts.
In one embodiment of PCT Application No. PCT/AU96/00324, the step of exposing the inside of the digestive tracts comprises eversion of the bodies. The eversion of the worm bodies may comprise drawing each worm body onto a pin located concentrically within a passage through which the worm body is fed longitudinally so that the pin partially enters the digestive tract but resistance to continued relative penetration of the pin into the digestive tract preferentially causes the worm body to evert so that the digestive tract is exposed on the outside of the worm body. The worm body may be split lengthwise after eversion so as to enable removal of the worm body from a processing zone where eversion has taken place.
In an alternative embodiment of said PCT application, the step of exposing the inside of the digestive tracts comprises splitting each worm body lengthwise so as to open the digestive tract of the worm lengthwise.
However, the applicant""s own prior art as described above may suffer certain disadvantages as follows:
(a) The prior schemes for splitting the worm bodies may be too slow in practice since the time taken to separate, align, and feed worms sequentially may make the throughput rate uneconomical. This may also make the previously proposed apparatus difficult and costly to implement to achieve viable production quantities.
(b) Worm bodies can vary substantially in diameter and length. In the prior art apparatus, there is little tolerance to processing of worms of different diameters. Therefore, there is a need for modified apparatus for processing different sizes of worms. Since lengths of worms can commonly be up to about 15 cm, the prior apparatus has greater difficulty in handling and: aligning such long worm bodies for splitting.
Therefore, there is a need for a simpler, more effective, and more economically viable apparatus and process for splitting the worm bodies.
It is therefore an object of the present invention to overcome or alleviate at least some of the drawbacks as stated above and to provide an apparatus for effectively processing worms.
It is also an object of the present invention to provide a more effective and preferably economically viable method for processing worms.
Accordingly, the present invention provides an apparatus for processing worms, the apparatus including:
spaced top and bottom surfaces set a sufficient distance apart so that worm bodies to be processed touch both surfaces when passing therebetween;
at least one splitter located between the surfaces and extending generally parallel to the surfaces to encounter worm bodies that travel between the surfaces, thereby splitting the worm bodies and;
means for applying force to the worm bodies to urge them between the two surfaces and onto the splitter so as to split the worm bodies lengthwise into segments.
In the present specification including in the claims, in interpreting references to xe2x80x9ctop and bottom surfacesxe2x80x9d, and later in this specification to xe2x80x9ctop platexe2x80x9d and xe2x80x9cbottom platexe2x80x9d which provide respectively the xe2x80x9ctop and bottom surfacesxe2x80x9d, it is to be understood that the use of xe2x80x9ctopxe2x80x9d and xe2x80x9cbottomxe2x80x9d in referring to the surfaces does not necessarily mean that the two surfaces are horizontal with the top one overlying the bottom one. Although this may be the preferred configuration, in practice the top and bottom surfaces can be inclined to the horizontal and indeed may even be both vertical. Also the surfaces need not necessarily be planar. For example, the surfaces could be generally conical or frusto conical and could be nested together with the required spacing between the surfaces.
In a preferred embodiment, the apparatus applies a centrifugal force to the worm bodies. For this purpose a rotor having spaced top and bottom plates provides respectively the top and bottom surfaces facing each other and spaced apart by the required distance. The rotor in use is arranged to be rotated about an axis passing through the top and bottom plates, preferably substantially through the centres thereof and the worm bodies when passing between the plates move outwardly from the axis of rotation under the radially acting centrifugal forces created by rotation of the rotor.
The means for applying force to the worm bodies includes means for creating a flow of fluid, preferably water, which applies force to the worm bodies to urge them between the two surfaces and onto the splitter.
The splitter may be a single splitter located substantially midway between the surfaces so as to split the worm bodies into two halves along a plane extending through the centres of the worm bodies when they are touching, and preferably partially flattened between, the top and bottom surfaces. The splitter may comprise a splitter blade although a splitter wire may also be possible. The splitter is preferably located so as to be operative to split the central digestive tracts of the worm bodies.
The apparatus preferably includes an inlet or a number of inlets located in the top surface through which the worm bodies are introduced into the space between the top and bottom surfaces. In the case of the apparatus including a rotor with spaced top and bottom plates, the inlet is preferably located substantially centrally at the centre of the top plate through which the axis of rotation of the rotor passes.
The inlet preferably has a flared inlet mouth leading into the space between the top and bottom plates into which worm bodies are introduced so that worm bodies of various diameters are compressed as they pass into the inlet mouth and into the space between the top and bottom surfaces to adopt a common thickness equal to the spacing of the top and bottom surfaces.
The apparatus may include adjustable spacing means enabling the spacing between the top and bottom surfaces to be selectively adjusted for processing differing diameters of worm bodies. The adjustable spacer means may include an arrangement for maintaining the splitter located substantially centrally between the top and bottom surfaces.
The apparatus preferably further includes a collecting zone located adjacent the top and bottom surfaces and into which the worm bodies pass after having been split lengthwise into segments thereby enabling collection of the segments for subsequent processing. In the preferred embodiment the collecting zone surrounds the periphery of the rotor to receive the worm bodies discharged under the centrifugal force.
There is also provided in a second aspect of the invention a method of processing worms including the steps of:
providing an apparatus which includes spaced top and bottom surfaces set a sufficient distance apart so that worm bodies to be processed touch both surfaces when passing therebetween and at least one splitter located between the surfaces and extending generally parallel to the surfaces to encounter worm bodies that travel between the surfaces;
introducing the worm bodies into the apace between the surfaces together with a sufficient flow of fluid; and
moving the worm bodies in the flow of fluid between the two surfaces and onto the splitter so as to split the worm bodies lengthwise into segments.
Preferably the step of moving the worm bodies includes applying a centrifugal force to the worm bodies.
In the preferred method for processing worms, the method includes the step of passing the worm bodies through a rotor providing spaced plates which define the top and bottom surfaces, the plates being set at a sufficient distance apart so that worm bodies touch both plates and are preferably partially flattened when passing therebetween, the splitter being located between and extending generally parallel to the plates. Preferably the rotor is rotated at sufficient speed to create centrifugal force acting on the worm bodies and on the water to promote movement of the worm bodies outwardly between the plates to encounter and to be split by the splitter. Preferably the rotational speed is also sufficient to cause the split worm bodies to be thrown outwardly from the periphery of the rotor and to impact against a wall of a collecting zone. Preferably, the impact of the split worm bodies onto the wall of the collecting zone is sufficient to force blood out of the blood vessels of the worm bodies.
The apparatus of the preferred embodiment of the present invention has a number of features working in combination:
i) spaced surfaces of the rotor plates between which worm bodies are introduced so that the worm bodies are at least slightly flattened between the two surfaces;
ii) a splitter located approximately mid-way between the two surfaces and being generally parallel to the surfaces in the region of the splitter; and
iii) means for applying force to the worm bodies to urge them between the two surfaces and onto the splitter so as to split the worm bodies lengthwise into segments.
In the preferred method, the worm bodies are introduced in the apparatus of the present invention with a sufficient flow of water which acts as a lubricant and to impart force on the worm bodies to move between the surfaces so that the worm bodies can slide outwardly between the two plates even though they are compressed between the plates at the same time. Without the introduction of the water in significant quantities, the worm bodies may tend to become stuck or jammed in the space between the plates and block further worm bodies travelling outwardly. However, if the rotational speed of the rotor is sufficiently greater, lesser quantities of water could be used. In a preferred embodiment, the centrifugal force created by the rotating rotor throws the water and split worm bodies radially outward from the periphery of the rotor and preferably onto the walls of a collecting zone, the impact of the split worm bodies onto the walls forcing blood out of blood vessels of the worm bodies.
Further cleansing of the split worm bodies may include washing the worm bodies by immersing and agitating the worm bodies in a washing medium so as to loosen remaining ingested matter enabling separation thereof from the bodies.